Maria Betti - Academia.edu (original) (raw)

Papers by Maria Betti

Research paper thumbnail of Single-particle and collective excitations of a two-dimensional electron gas at the Cs/InAs(110) surface

Physical review, Oct 19, 2001

Research paper thumbnail of Electron energy‐loss spectroscopy investigation of core levels and valence excitations of Pd2Si

Journal of vacuum science & technology, Jul 1, 1987

An electron energy-loss spectroscopy investigation of Pd2Si valence band and core edges is presen... more An electron energy-loss spectroscopy investigation of Pd2Si valence band and core edges is presented. The interpretation of the different observed structures allows us to understand the changes which occur in full (d bonding) and empty (s,p antibonding) electronic states on passing from pure Pd to the Pd2Si compound. The local structure around the Pd atom is derived through the analysis of the extended loss features above the N2,3 levels.

Research paper thumbnail of High resolution electron energy loss spectroscopy study of the SbGaAs(110) system

Research paper thumbnail of High resolution electron energy loss investigation of the azimuthal dependence of the Si(111)(2x1) surface excitations

Surface Science Letters, Oct 1, 1987

ABSTRACT

Research paper thumbnail of Collective and vibrational excitations on then-doped GaAs(110) surface

Physical review, Mar 15, 1989

ABSTRACT

Research paper thumbnail of Loss features in the HREEL spectra of the K/GaAs(110) system

We investigated the evolution of the space-charge layer at the GaAs(110) surface as a function of... more We investigated the evolution of the space-charge layer at the GaAs(110) surface as a function of the potassium coverage by means of HREELS, looking at the surface coupled collective excitations (phonon-plasmon, i.e. plasmarons

Research paper thumbnail of High resolution electron energy loss investigation of the azimuthal dependence of the Si(111)(2×1) surface excitations

Surface Science, Oct 1, 1987

Electron energy loss spectroscopy has been used, with low energy of the primary beam and azimutha... more Electron energy loss spectroscopy has been used, with low energy of the primary beam and azimuthal resolution, to study the anisotropy of the surface vibrational and electronic properties of the cleavage surface of silicon. The analysis of the loss function has been performed through the substraction of the kinematic prefactor accounting for the finite angular acceptance of the spectrometer. The

Research paper thumbnail of Heisenberg’s uncertainty principle in the PTOLEMY project: A theory update

Research paper thumbnail of Implementation and optimization of the PTOLEMY transverse drift electromagnetic filter

Journal of Instrumentation

The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy s... more The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium β-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter for electrons with a known pitch angle. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-we...

Research paper thumbnail of Magnetic response and electronic states of well defined Graphene/Fe/Ir(111) heterostructure

Physical Review Materials, 2021

Research paper thumbnail of Low Field Optimization of the PTOLEMY Electromagnetic Filter Low Field Optimization of the PTOLEMY Electromagnetic Filter

Low Field Optimization of the PTOLEMY Electromagnetic Filter A. Apponi,1, 2 M.G. Betti,3, 4 M. Bo... more Low Field Optimization of the PTOLEMY Electromagnetic Filter A. Apponi,1, 2 M.G. Betti,3, 4 M. Borghesi,5, 6 A. Boscá,7 F. Calle,7 N. Canci,8 G. Cavoto,3, 4 C. Chang,9, 10 W. Chung,11 A.G. Cocco,12 A.P. Colijn,13, 14 N. D’Ambrosio,8 N. de Groot,15 M. Faverzani,5, 6 A. Ferella,8, 16 E. Ferri,5 L. Ficcadenti,3, 4 P. Garcia-Abia,17 G. Garcia Gomez-Tejedor,18 S. Gariazzo,19 F. Gatti,20 C. Gentile,21 A. Giachero,5, 6 Y. Hochberg,22 Y. Kahn,10, 23 A. Kievsky,24 M. Lisanti,11 G. Mangano,12, 25 L.E. Marcucci,24, 26 C. Mariani,3, 4 J. Martínez,7 M. Messina,8 E. Monticone,19, 27 A. Nucciotti,5, 6 D. Orlandi,8 F. Pandolfi,3 S. Parlati,8 J. Pedrós,7 C. Pérez de los Heros,28 O. Pisanti,12, 25 A.D. Polosa,3, 4 A. Puiu,8, 29 I. Rago,3, 4 Y. Raitses,21 M. Rajteri,19, 27 N. Rossi,8 K. Rozwadowska,8, 29 I. Rucandio,17 A. Ruocco,1, 2 R. Santorelli,17 C.F. Strid,30 A. Tan,11 C.G. Tully,11 M. Viviani,24, 26 U. Zeitler,15 and F. Zhao11 1)INFN Sezione di Roma 3, Roma, Italy 2)Università di Roma Tre, Roma,...

Research paper thumbnail of Towards free-standing graphane: atomic hydrogen and deuterium bonding to nano-porous graphene

Nanotechnology, 2020

Graphane is formed by bonding hydrogen (and deuterium) atoms to carbon atoms in the graphene mesh... more Graphane is formed by bonding hydrogen (and deuterium) atoms to carbon atoms in the graphene mesh, with modification from the pure planar sp2 bonding towards an sp3 configuration. Atomic hydrogen (H) and deuterium (D) bonding with C atoms in fully free-standing nano porous graphene (NPG) is achieved, by exploiting low-energy proton (or deuteron) non-destructive irradiation, with unprecedented minimal introduction of defects, as determined by Raman spectroscopy and by the C 1s core level lineshape analysis. Evidence of the H- (or D-) NPG bond formation is obtained by bringing to light the emergence of a H- (or D-) related sp3-distorted component in the C 1s core level, clear fingerprint of H–C (or D–C) covalent bonding. The H (or D) bonding with the C atoms of free-standing graphene reaches more than 1/4 (or 1/3) at% coverage. This non-destructive H-NPG (or D-NPG) chemisorption is very stable at high temperatures up to about 800 K, as monitored by Raman and x-ray photoelectron spectr...

Research paper thumbnail of Insight into the electronic structure of semiconducting ε−GaSe and ε−InSe

Physical Review Materials, 2020

Research paper thumbnail of An experimental and theoretical study of metallorganic coordination networks of tetrahydroxyquinone on Cu(111)

New Journal of Chemistry, 2019

DFT modeling of STM and XAS evidences investigated the adsorption of THQ@Cu(111) that generates d... more DFT modeling of STM and XAS evidences investigated the adsorption of THQ@Cu(111) that generates different ordered configurations at different temperatures.

Research paper thumbnail of Mixing of MnPc electronic states at the MnPc/Au(110) interface

The Journal of Chemical Physics, 2017

Manganese-phthalocyanines form assembled chains with a variety of ordered super-structures, flat ... more Manganese-phthalocyanines form assembled chains with a variety of ordered super-structures, flat lying along the Au(110) reconstructed channels. The chains first give rise to a ×5 symmetry reconstruction, while further deposition of MnPc leads to a ×7 periodicity at the completion of the first single layer. A net polarization with the formation of an interface dipole is mainly due to the molecular π-states located on the macrocycles pyrrole rings, while the central metal ion induces a reduction in the polarization, whose amount is related to the Mn-Au interaction. The adsorption-induced interface polarization is compared to other 3d-metal phthalocyanines, to unravel the role of the central metal atom configuration in the interaction process of the d-states. The MnPc adsorption on Au(110) induces the re-hybridization of the electronic states localized on the central metal atom, promoting a charge redistribution of the molecular orbitals of the MnPc molecules. The molecule-substrate i...

Research paper thumbnail of Topology and doping effects in three-dimensional nanoporous graphene

Research paper thumbnail of Graphene-mediated interaction between FePc and intercalated cobalt layers

Applied Surface Science, 2018

Research paper thumbnail of Chemical Vapor Deposition Growth of Boron-Carbon-Nitrogen layers from Methylamine Borane Thermolysis Products

Nanotechnology, Jan 21, 2017

This work investigates the growth of B-C-N layers by Chemical Vapor Deposition using methylamine ... more This work investigates the growth of B-C-N layers by Chemical Vapor Deposition using methylamine borane (MeAB) as single-source precursor. MeAB has been synthesized and characterized, paying particular attention to the analysis of its thermolysis products, which are the gaseous precursors for B-C-N growth. Samples have been grown on Cu foils and transferred onto different substrates for their morphological, structural, chemical, electronic and optical characterizations. The results of these characterizations indicate a segregation of h-BN and Graphene-like (Gr) domains. However, there is an important presence of B and N interactions with C at the Gr borders, and of C interacting at the h-BN-edges, respectively, in the obtained nano-layers. In particular, there is significant presence of C-N bonds, at Gr/h-BN borders and in the form of N doping of Gr domains. The overall B:C:N contents in the layers is close to 1:3:1.5. A careful analysis of the optical bandgap determination of the o...

Research paper thumbnail of Effect of substrate polishing on the growth of graphene on 3C–SiC(111)/Si(111) by high temperature annealing

Research paper thumbnail of Graphene nanoribbons synthesized from molecular precursor polymerization on Au(110)

AIP Conference Proceedings, 2015

Research paper thumbnail of Single-particle and collective excitations of a two-dimensional electron gas at the Cs/InAs(110) surface

Physical review, Oct 19, 2001

Research paper thumbnail of Electron energy‐loss spectroscopy investigation of core levels and valence excitations of Pd2Si

Journal of vacuum science & technology, Jul 1, 1987

An electron energy-loss spectroscopy investigation of Pd2Si valence band and core edges is presen... more An electron energy-loss spectroscopy investigation of Pd2Si valence band and core edges is presented. The interpretation of the different observed structures allows us to understand the changes which occur in full (d bonding) and empty (s,p antibonding) electronic states on passing from pure Pd to the Pd2Si compound. The local structure around the Pd atom is derived through the analysis of the extended loss features above the N2,3 levels.

Research paper thumbnail of High resolution electron energy loss spectroscopy study of the SbGaAs(110) system

Research paper thumbnail of High resolution electron energy loss investigation of the azimuthal dependence of the Si(111)(2x1) surface excitations

Surface Science Letters, Oct 1, 1987

ABSTRACT

Research paper thumbnail of Collective and vibrational excitations on then-doped GaAs(110) surface

Physical review, Mar 15, 1989

ABSTRACT

Research paper thumbnail of Loss features in the HREEL spectra of the K/GaAs(110) system

We investigated the evolution of the space-charge layer at the GaAs(110) surface as a function of... more We investigated the evolution of the space-charge layer at the GaAs(110) surface as a function of the potassium coverage by means of HREELS, looking at the surface coupled collective excitations (phonon-plasmon, i.e. plasmarons

Research paper thumbnail of High resolution electron energy loss investigation of the azimuthal dependence of the Si(111)(2×1) surface excitations

Surface Science, Oct 1, 1987

Electron energy loss spectroscopy has been used, with low energy of the primary beam and azimutha... more Electron energy loss spectroscopy has been used, with low energy of the primary beam and azimuthal resolution, to study the anisotropy of the surface vibrational and electronic properties of the cleavage surface of silicon. The analysis of the loss function has been performed through the substraction of the kinematic prefactor accounting for the finite angular acceptance of the spectrometer. The

Research paper thumbnail of Heisenberg’s uncertainty principle in the PTOLEMY project: A theory update

Research paper thumbnail of Implementation and optimization of the PTOLEMY transverse drift electromagnetic filter

Journal of Instrumentation

The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy s... more The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium β-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter for electrons with a known pitch angle. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-we...

Research paper thumbnail of Magnetic response and electronic states of well defined Graphene/Fe/Ir(111) heterostructure

Physical Review Materials, 2021

Research paper thumbnail of Low Field Optimization of the PTOLEMY Electromagnetic Filter Low Field Optimization of the PTOLEMY Electromagnetic Filter

Low Field Optimization of the PTOLEMY Electromagnetic Filter A. Apponi,1, 2 M.G. Betti,3, 4 M. Bo... more Low Field Optimization of the PTOLEMY Electromagnetic Filter A. Apponi,1, 2 M.G. Betti,3, 4 M. Borghesi,5, 6 A. Boscá,7 F. Calle,7 N. Canci,8 G. Cavoto,3, 4 C. Chang,9, 10 W. Chung,11 A.G. Cocco,12 A.P. Colijn,13, 14 N. D’Ambrosio,8 N. de Groot,15 M. Faverzani,5, 6 A. Ferella,8, 16 E. Ferri,5 L. Ficcadenti,3, 4 P. Garcia-Abia,17 G. Garcia Gomez-Tejedor,18 S. Gariazzo,19 F. Gatti,20 C. Gentile,21 A. Giachero,5, 6 Y. Hochberg,22 Y. Kahn,10, 23 A. Kievsky,24 M. Lisanti,11 G. Mangano,12, 25 L.E. Marcucci,24, 26 C. Mariani,3, 4 J. Martínez,7 M. Messina,8 E. Monticone,19, 27 A. Nucciotti,5, 6 D. Orlandi,8 F. Pandolfi,3 S. Parlati,8 J. Pedrós,7 C. Pérez de los Heros,28 O. Pisanti,12, 25 A.D. Polosa,3, 4 A. Puiu,8, 29 I. Rago,3, 4 Y. Raitses,21 M. Rajteri,19, 27 N. Rossi,8 K. Rozwadowska,8, 29 I. Rucandio,17 A. Ruocco,1, 2 R. Santorelli,17 C.F. Strid,30 A. Tan,11 C.G. Tully,11 M. Viviani,24, 26 U. Zeitler,15 and F. Zhao11 1)INFN Sezione di Roma 3, Roma, Italy 2)Università di Roma Tre, Roma,...

Research paper thumbnail of Towards free-standing graphane: atomic hydrogen and deuterium bonding to nano-porous graphene

Nanotechnology, 2020

Graphane is formed by bonding hydrogen (and deuterium) atoms to carbon atoms in the graphene mesh... more Graphane is formed by bonding hydrogen (and deuterium) atoms to carbon atoms in the graphene mesh, with modification from the pure planar sp2 bonding towards an sp3 configuration. Atomic hydrogen (H) and deuterium (D) bonding with C atoms in fully free-standing nano porous graphene (NPG) is achieved, by exploiting low-energy proton (or deuteron) non-destructive irradiation, with unprecedented minimal introduction of defects, as determined by Raman spectroscopy and by the C 1s core level lineshape analysis. Evidence of the H- (or D-) NPG bond formation is obtained by bringing to light the emergence of a H- (or D-) related sp3-distorted component in the C 1s core level, clear fingerprint of H–C (or D–C) covalent bonding. The H (or D) bonding with the C atoms of free-standing graphene reaches more than 1/4 (or 1/3) at% coverage. This non-destructive H-NPG (or D-NPG) chemisorption is very stable at high temperatures up to about 800 K, as monitored by Raman and x-ray photoelectron spectr...

Research paper thumbnail of Insight into the electronic structure of semiconducting ε−GaSe and ε−InSe

Physical Review Materials, 2020

Research paper thumbnail of An experimental and theoretical study of metallorganic coordination networks of tetrahydroxyquinone on Cu(111)

New Journal of Chemistry, 2019

DFT modeling of STM and XAS evidences investigated the adsorption of THQ@Cu(111) that generates d... more DFT modeling of STM and XAS evidences investigated the adsorption of THQ@Cu(111) that generates different ordered configurations at different temperatures.

Research paper thumbnail of Mixing of MnPc electronic states at the MnPc/Au(110) interface

The Journal of Chemical Physics, 2017

Manganese-phthalocyanines form assembled chains with a variety of ordered super-structures, flat ... more Manganese-phthalocyanines form assembled chains with a variety of ordered super-structures, flat lying along the Au(110) reconstructed channels. The chains first give rise to a ×5 symmetry reconstruction, while further deposition of MnPc leads to a ×7 periodicity at the completion of the first single layer. A net polarization with the formation of an interface dipole is mainly due to the molecular π-states located on the macrocycles pyrrole rings, while the central metal ion induces a reduction in the polarization, whose amount is related to the Mn-Au interaction. The adsorption-induced interface polarization is compared to other 3d-metal phthalocyanines, to unravel the role of the central metal atom configuration in the interaction process of the d-states. The MnPc adsorption on Au(110) induces the re-hybridization of the electronic states localized on the central metal atom, promoting a charge redistribution of the molecular orbitals of the MnPc molecules. The molecule-substrate i...

Research paper thumbnail of Topology and doping effects in three-dimensional nanoporous graphene

Research paper thumbnail of Graphene-mediated interaction between FePc and intercalated cobalt layers

Applied Surface Science, 2018

Research paper thumbnail of Chemical Vapor Deposition Growth of Boron-Carbon-Nitrogen layers from Methylamine Borane Thermolysis Products

Nanotechnology, Jan 21, 2017

This work investigates the growth of B-C-N layers by Chemical Vapor Deposition using methylamine ... more This work investigates the growth of B-C-N layers by Chemical Vapor Deposition using methylamine borane (MeAB) as single-source precursor. MeAB has been synthesized and characterized, paying particular attention to the analysis of its thermolysis products, which are the gaseous precursors for B-C-N growth. Samples have been grown on Cu foils and transferred onto different substrates for their morphological, structural, chemical, electronic and optical characterizations. The results of these characterizations indicate a segregation of h-BN and Graphene-like (Gr) domains. However, there is an important presence of B and N interactions with C at the Gr borders, and of C interacting at the h-BN-edges, respectively, in the obtained nano-layers. In particular, there is significant presence of C-N bonds, at Gr/h-BN borders and in the form of N doping of Gr domains. The overall B:C:N contents in the layers is close to 1:3:1.5. A careful analysis of the optical bandgap determination of the o...

Research paper thumbnail of Effect of substrate polishing on the growth of graphene on 3C–SiC(111)/Si(111) by high temperature annealing

Research paper thumbnail of Graphene nanoribbons synthesized from molecular precursor polymerization on Au(110)

AIP Conference Proceedings, 2015